Refining oil



July 7, 1925. '1,544,734

L. D. FULTON REFIN'ING OIL Filed July 20. 1922 COIL FUR TREHTEH OIL TR T EH E0 UIL CdlL F01? HEFFGERHIIT 1N VEN TOR ourLEr-com 0 ATTORNEY Patented July 7, 1,9725. z

UNITED STATES 1,544,734 PATENT oFF'lci-z.

LUTHER D. FULTON, OF TITUSVILLE, IPENNSYLVANIA, ASSIGNOB TO THE DE LAVAL SEPARATOR COMPANY, .A CORPORATION F NEW JERSEY. l

BEFINING OIL.

Application led July 20, 1922. VSerial No. 576,211.

To all wlmm it may concern.'

Be it known that I, LUTHER D. FULTON, a citizen of the United States, residing at Titusville, in the county of Crawford, State of Pennsylvania, have invented certain new and useful Improvements in Refining Oil;

and I do hereby declare the following to, be a full, clear, and exact description of the a large tank or tower and bringing it first` into heat interchanging relation with the cold oil from which the wax has beenseparated and then into indirect contact with a coolingfo'r refrigerating agent at a lower temperature, and finally the wax is separated from the oil by contrifugal force. The cold oil from which the wax has been separated is then returned for preliminary cooling the oil flowing downwardly through the f tank or tower.

The circulation of the warm oil in heat interchanging relation with the cold oil in the top of the tank or tower is a countercurrent circulation so that the warm oil is progressively cooled and the coldV oil progressively warmed. The circulation of the oil in heatinterchanging relation with the cooling or refrigerating fluid in the lower part of the tank or tower is also a countercurrent circulation, so thatthe oil entering the top of the tank or tower as warm oil, and which is preliminarily cooled by heat interchange with the `cold oil from the centrifugal separator, is further gradually cooled counter-current heat interchange with cooling or refrigerating fluid.

The body of the oilv in the tank or tower is thus graduallyand progressively cooled during its downward flow, and sudden chilling or sharp freezing of the oil is prevented. This slow and gradual cooling of` the oil is particularly advantageous in permitting the wax to separate from the oil in a form well adapted for subsequent removal in a centrifugal separator.

The invention will be further described in connection with accompanying drawing illustrating one embodiment of the apparatus of the invention adapted for the practice of the process of the invention. The figure shown in the drawing is -in part a verticalsectional view and in part an elevation, with parts shown more or less conventionally for purposes of illustration.

In the apparatus illustrated in the drawing a large container 10 is provided in the form of a vertical tank or tower, which may be made of metal and which is provided with an outer covering 11 of insulating materal .and enclosed within an outer casing 12 of'brlck or similar material.

Located within the tank or tower 10 are upper and lower coils 13 and 14 respectively. Each of these coils is made up of several horizontal layers, and each layer is made up of a series of pipes extending back and forth, so that a series of pipes (eight in the apparatus shown) are arranged at each layer, and these pipes are uniformly distributed over the horizontal cross-section of the tower. A part of the layers of pipe are arranged with the ipipes at right angles to the pipes of other layers, as illustrated. This arrange- V ment insures that the oil flowing down through the tank or tower is brought into intimate Contact with theY coils so that effective heat exchange will take place.

The coil 13 has an inlet 15 leading fromthe centrifugal separator for introducing the cold Voil from the separator into the coil. The oil passing' out at 16 goes to any suitable storage.

The lower coil 14 has its inlet 18 comammonia. The outlet 19 from the coil may -return to the refrigerating system from which the refrigerating fluid is supplied.

The tower is provided with an inlet 20 for the oil to be cooled. A distributing plate or perforated baille 21 serves to distribute the oil evenly in the top of the tower. The tower'is intended to be'kept full of oil to approximately the level of the distributing plate. A11 overiow pipe 23 is provided to prevent the oil level from risin too high and a sight-glass 24 is provided or indicating the oil level. Provision is also made for automatically controlling the oil level4 and the amount of oil entering the apparatus.

For example, in the apparatus illustrated,

' a loat, 25 is provided, carried by the rocker arm 26 and the latter lias suitable communication 27 with a pump governor or balanced valve 28, shown conventionally, which controls the supply of oil pumped into the tank. Float controlled automatic regulating devices of this kind are well known and for this reason thespecific construction has not been illustrated.

At the bottom of the tower 10-is the outlet 22 from which the cold oil flows through the pipe 33 to the centrifugal separator 34. This separator may be of known construction and may operate either with or without va carrier liquid for'assisting in the centrifugal separation of the wax from t-he oil.

' From the centrifugal separator the oil,

freed from wax, is pumped back to the coil 13 through pipe 15 b the pump 35. l

At the bottom of t e tower is an agitator" 29 driven by gears 31 and the drive shaft 30.

This agitator can be operated more or less slowly to prevent the wax from settling out on the bottom of the tower, but in practice, if the operation. is properly regulated, I have found that such agitation is not necessary, and when used, only a relatively small amount of agitation is required, and the agitation should not besuch as will agitate any considerable amount ofthe body of oil in the tower. Y

In the operation of the apparatus, the charging stock or oil from which the wax is to be sepa-rated is introduced at the top/of the towenthrough the pipe 20 and is spread out more or less uniformly by the'distributing plate 21. This warm oil flows slowly` down through the tower where it comes 1n contact first with Fthe cooling coil 13 and where the temperature is slowly and progressively lowered by the counter-current heat exchange with the cold oil flowing upwardly through the coil. The precooled oil then flows down in heat interchanging relation with the'refr'igerating coil 14 and comes in contact first with the warmer part of this coil and finally -with the coldest part at ythe bottom. A gradual and progressive cooling of the entire body of oil thus takes place and the wax is in this way separated from the oil in a manner which enables itl to be readily recovered from the oil by centrifugal force. It will be seen that the body of oil slowly moving downwardly through the tower is maintained in a quiescent state without any rapid agitation and with only slow downward movement andv gradual and progressive slow cooling to permit the desired crystallization or recipitation'of wax from the oil. This gra ual and progressive cooling of the oil without a marked difference of temperature between the oil and the cooling medium at any point in the tower is particularly important and the construction,`

of this apparatus is such that it is attained to a marked degree. The oil o'wing from the separator into the cooling coil 13 isat an intermediate temperature but little below the temperature of thel oil in the tower at that point, and its temperature is raised as it Hows upward through the coil 13. Also, the brine or other-cooling medium in coil 14 is raised in temperature as it flows upward so that at the outlet of the coil 14 its temperature is only 'a little below that of the oil at the inlet of coil 13. Thel oil which has thus been prepared for centrifugal separation of wax therefrom vis then conveyed Vto the centrifugal separator, in

which the wax is separated by centrifugal force, and the coldoil is then returned for use in the preliminary cooling of the warm entering/oil.

The downward flow of the oil in the tower, and the supply ofV warm oil at the-top, results in keeping the oil'at the top of the tower warm so. that trouble from moisture or particles of ice is eliminated. The downward How of the oil also assists in preventing settling out of the wax at the bottom of The oil and wax are of nearly l the tower. the same specific gravity so that by proper- 1y regulating the rate of ow of the oil and the rate at which its temperature is lowered, it ispossible to secure a balance in conditions Such that the precipitating waxy does not settle out of theoil at the bottom of the tower, but is carried along and discharged with the oil. The relative rates of flow and -of coolingy necessary to produce this condition will, to a large extent, depend on the dimensions of the tower, the area of the cooling surfaces, etc., but may be readily determined in the actual operation,

of the tower. I have also found thatj with gradual down'ow of oil through lthe tower and with progressive cooling and separation of wax without any sudden or sharp change in temperature, the wax comes out of v solution in a condition well adapted forL centrifugal separation. The oil which is to be treated' according to the present invention may vary in character, both in the nature and amount of wax llO to be separated, and in the character of the scope'ofthe in- The method of separating wax fom mineral oils containing the same solution, whichL comprises slowly flowing a large volume of oil along a downward path wlthout agitation and without substantial change of direction, the oilbeing maintained in a stream of large cross-sectional area as compared with the length of its path of travel, subjecting the flowing oil to gradual and progressive cooling by indirect contact with a cooling medium, passing upwardly countercurrent to the flowing oil, and subjecting the oil so cooled to centrifugal separation.

2. The method of separating wax from mineral oils containing the same in solution, which comprises slowly flowing a large volume of oil along a downward path without agitation and without substantial change of direction, the oil being maintained ina stream of large cross-sectional area. as compared with the length of its path of travel, subjecting'the flowing oil to gradual and progressive' cooling by indirect contact with a cooling medium flowing upwardly coun? ter-current to the down-flow of oil, maintaining such a relation between the velocity of the oil and the rate of cooling that the settling of the precipitated wax from the oil is -substantially prevented, and subjecting the cold oil to centrifugal separation.

3. The method of separating wax from mineral oils containing the same in solutionwhich comprises slowly flowing a large volume of oil along a downward path without agitation and without substantial change of direction, the oil being maintained in a` stream of large cross-sectional area as com- `pared with the length of its path of travel,

subjecting the flowing oil to gradual and progressive cooling by indirect contact with treated oil and then with a cooling medium at a low temperature, the treated oil and cooling medium flowing upwardly countercurrent to the down-flow of untreated oil, and subjecting the resulting cold oil to oentrifugal separation, the cold oil after the centrifugal separation ofthe wax therefrom, being that used for preliminarily cooling the untreated oil.

4. Apparatus for the separation of wax from mineral oils comprising the combination of a large container adapted to permit the flow of a large body of untreated oil therethrough, without substantial change 'of direction and without substantial agitation, an inlet for the oil at the top of the container and an outletfor the oil at the bottom of '|56 the container, a centrifugal separator for relceiving the oil from the bottom of the conpart of the container whereby the moving body of untreated oil passing through the container is progressively' cooled, first by heat interchange with cold treated oil and later with the refrigerating agent.

5. Apparatus for the separation of wax from mineral oils which comprises the combination of a large container adapted to permit the flow therethrough of a large body of untreated oil -without substantial agitation f and without substantial change in direction, and having an inlet at the top and an outlet at the bottom, a cen: trifugal separator for receiving the oil fom the bottom of the container, a coil arranged in the upper part of the container, means for circulating the cold treated .oil from the centrifugal separator through said coil in a generally upward direction, and another coil arranged in the container' below the first coil and adapted for the circulation therethrough of a refrigerating agent in a generally upward direction, both said coils being arranged to provide an extended cooling surface distributed throughout the moving body of oil whereby the temperature of 90 the latter is gradually and progressively lowered.

6. An apparatus for the separation of wax from mineral oils comprising a large container adapted to containa large body of oil and having an inlet at the top and an outlet at the bottom, means for distributing the oil entering at the top of the container, means for"maintaining the level of oil in said container, cooling means in said container adapted for the circulation upwardly therethrough of a cooling fiuid, and a centrifugal separator arranged to receive the cold oil from the nbottom of said container, and to Separate the wax therel from.

In testimony whereof I affix my signature.A

LUTHER D. FULTON. 

